In a liquid crystal display panel, a display region is formed such that a TFT substrate over which pixel electrodes and thin-film transistors (TFTs), inter alia, are formed in a matrix and an opposing substrate over which color filters, inter alia, are formed in positions corresponding to the pixel electrodes in the TFT substrate are placed facing each other and liquid crystals are sandwiched between the TFT substrate and the opposing substrate. An image is produced by controlling light transmissibility through liquid crystal molecules pixel by pixel. Since liquid crystals are able to control only polarized light, light from a backlight is polarized by a lower polarizing plate before entering the TFT substrate and, after being subjected to control by a liquid crystal layer, the light is polarized again by an upper polarizing plate and goes out. Thus, outgoing light from the liquid crystal display panel is polarized light.
Various methods for converting an image produced by a liquid crystal display panel to a three-dimensional image have been proposed. Among them, a method of placing a liquid crystal lens on the top of a liquid crystal display panel attracts attention particularly for compact display devices, because special glasses are not needed for visual perception of a three-dimensional image and switching between a two-dimensional image and a three-dimensional image is possible.
Meanwhile, there is a requirement to reduce the entire thickness of a liquid crystal display device and, consequently, reducing the thickness of a liquid crystal display panel is pursued. Thinning the liquid crystal display panel is accomplished by abrading the TFT substrate and the opposing substrate. As a result, the mechanical strength of the liquid crystal display panel becomes problematic. Japanese Published Unexamined Patent Application No. Hei 9-146078 describes a structure in which, out of the TFT substrate and the opposing substrate, the thickness of the opposing substrate is made larger in order to maintain the strength of the layered liquid crystal display panel.
Meanwhile, Japanese Published Unexamined Patent Application No. Hei 11-15012 describes a structure of a laminated liquid crystal display device having three or more liquid crystal layers, in which the thicknesses of two outermost substrates are kept large, while the thicknesses of substrates sandwiching a liquid crystal layer between them are reduced, thereby decreasing vision disparity.